Surgical access assembly and method of using same

ABSTRACT

A surgical access assembly is disclosed. The surgical access assembly comprises an outer sheath and an obturator. The outer sheath is defined by an open distal end and an open proximal end and includes a hollow body portion therebetween. The obturator is defined by a distal end and a proximal end and the distal end further comprises a tapered distal tip member that terminates in a closed radiused distal tip. The obturator is configured to be received within the outer sheath such that the tapered distal tip member protrudes from the open distal end of the outer sheath when the obturator is in an introducing configuration.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of co-pending U.S. patentapplication Ser. No. 13/280,015.

TECHNICAL FIELD

The present disclosure relates generally to a surgical device for usewith delicate and critical tissues, as well as methods of accessing andperforming surgery using same. The present disclosure also relates totreatment of a surgical site.

BACKGROUND

Diagnosis and treatment of conditions affecting the brain are among themost difficult and complex problems that face the medical profession.The brain is a complex and delicate soft multi-component tissuestructure that controls bodily functions through a complex neuralnetwork connected to the rest of the body through the spinal cord. Thebrain and spinal cord are contained within and protected by significantbony structures, e.g., the skull and the spine. Given the difficulty ofaccessing the brain through the hard bony protective skull and thedelicate network and complex interactions that form the neuralcommunication network contained within the brain that define the humanbody's ability to carry on its functions of speech, sight, hearing,functional mobility, reasoning, emotions, respiration and othermetabolic functions, the diagnosis and treatment of brain disorderspresents unique challenges not encountered elsewhere in the body.

For example, abnormalities such as intracranial cerebral hematomas(ICH), abscesses, glioblastomas (GB) and metastases (mets) manifestthemselves in the intraparenchymal subcortical space (i.e., the whitematter) of the brain are particularly challenging to access, let alonetreat. The ventricles of the brain contain eloquent communicationstructures (neural network) which are located in the subcortical space,called fiber tracts and fascicles. Thus, traditionally, unless the ICH,GB, and/or mets where considered anything but “superficial,” suchconditions have been considered inoperable, simply because getting tothe abnormality ICH, GB and/or mets are considered just as damaging asletting the condition take its course. Similarly, tissue abnormalitiessuch as tumors, cysts and fibrous membrane growths which manifest withinthe intraventricular space of the brain are considered challenging tosafely access and often inoperable, due to their locations within thebrain.

In order to assist in diagnosis and subsequent treatment of braindisorders, clear, accurate imaging of brain tissue through the skull isrequired. In recent years significant advances have been made in imagingtechnology, including stereotactic X-ray imaging, Computerized AxialTomography (CAT), Computerized Tomographic Angiography (CTA), PositionEmission Tomography (PET) and Magnetic Resonance Imaging (MRI),Diffusion Tensor Imaging (DTI) and Navigation systems (instrumentposition tracking systems). These imaging devices and techniques permitthe surgeon to observe conditions within the brain in a non-invasivemanner without opening the skull, as well as provide a map of criticalstructures surrounding an area of interest, including structures such asblood vessels, membranes, tumor margins, cranial nerves, including fibertracts and fascicles. If an abnormality is identified through the use ofone or more imaging modalities and/or techniques, it may be necessary ordesirable to biopsy or remove the abnormality.

Once a course of action has been determined based upon one or moreimaging techniques, a surgical treatment may be necessary or desired. Inorder to operate surgically on the brain, access must be obtainedthrough the skull and delicate brain tissue containing blood vessels andnerves that can be adversely affected by even slight disturbances.Therefore, great care must be taken in operating on the brain so as notto disturb delicate blood vessels and nerves to prevent adverseconsequences resulting from a surgical intervention.

Traditionally, accessing abnormalities which manifest in deeper spaceswithin the brain has meant a need for a surgery that creates a highlyinvasive approach. In some instances, in order to obtain access totarget tissue, a substantial portion of the skull is removed and entiresections of the brain are retracted to obtain access. For example,surgical brain retractors are used to pull apart or spread delicatebrain tissue, which can leave pressure marks from lateral edges of theretractor. In some instances, a complication known as “retractioninjury” may occur due to use of brain retractors. Of course, suchtechniques are not appropriate for all situations, and not all patientsare able to tolerate and recover from such invasive techniques.

It is also known to access certain portions of the brain by creating aburr hole craniotomy, but only limited surgical techniques may beperformed through such smaller openings. In addition, some techniqueshave been developed to enter through the nasal passages, opening anaccess hole through the occipital bone to remove tumors located, forexample, in the area of the pituitary. These approaches are referred toas Expanded Endonasal Approaches (EEA) and were pioneered by one of theinventors of this disclosure.

A significant advance in brain surgery is stereotactic surgery involvinga stereotactic frame correlated to stereotactic X-ray images to guide anavigational system probe or other surgical instrument through anopening formed in the skull through brain tissue to a target lesion orother body. A related advance is frameless image guidance, in which animage of the surgical instrument is superimposed on a pre-operativeimage to demonstrate the location of the instrument to the surgeon andtrajectory of further movement of the probe or instrument.

In recent years, surgical access systems have been developed to provideaccess to previously difficult to access areas. One such prior artsystem is shown in FIGS. 1A-1C. System 10 includes a retractor 20 and anintroducer 40. Introducer 40 includes a cone-shaped distal end 42 withan opening 52 therein (best seen in FIG. 1C). The cone-shaped distal endis configured to be a generally blunt, flat surface. With introducer 40positioned within retractor 10, system 10 is inserted into brain tissue,thereby pushing brain tissue away while providing access to an area ofinterest. Once system 10 is delivered to the area of interest, retractor10 is rigidly fixed in position. More specifically, retractor 10 isfixed in space with the use of a standard or conventional neurosurgicalfixation device. Once, retractor 10 is fixed in place, introducer 40 isthen removed from retractor 10, while leaving retractor 10 in its fixedplace, thereby creating a pathway through the brain tissue.

While access system 10 may provide a manner to access certain braintissue, the blunt shaped distal end of can actually cause transient oreven permanent deformation and trauma of delicate tissue structureswhich can manifest itself in temporary or permanent neurologicaldeficits after surgical cytoreduction due to damage of blood vessels,cranial nerves, fiber tracts and fascicles. Opening 52 may cause coringof tissue, also leading to damage of the tissues and structures asintroducer 40 is pushed through tissue. Further, by rigidly fixing theplacement of retractor 10, manipulation of retractor 10 is impeded andrequires constant attention by loosening and retightening to re-positionfor even micro-movement of the retractor 10, thereby lengtheningprocedure time.

Another issue that needs to be addressed is visibility. Typically whenemploying an access system in a surgical procedure, it is often likeoperating in a poorly lit tunnel. To provide illumination, it is knownto place a light source within the introducer sheath, such as anendoscope. However, when using an endoscope, the light source takes up asignificant amount of working space within the introducer sheath, thusreducing the functional working area for other instruments, as well asminimizing the ability to move other instruments within the surgicalsite.

Alternatively, light must be delivered from a remote or externallocation, such as a microscope or exoscope. However, in the case ofmicroscopes and exoscopes, the external light source is often blocked bythe surgeon and/or instruments in the surgical field. At a minimum, theeffectiveness is greatly diminished at the distal end of the introducersheath where the actual surgical work and/or treatment is occurring, andwhere effective visualization is needed the most.

Notwithstanding the foregoing advances in imaging technology and bothframe and frameless stereotactic image guidance techniques, thereremains a need for improved surgical techniques and apparatus foroperating on brain tissue.

There also exists a need for improved and effective treatment regimensand options. Traditionally, once diseased tissue is removed,traditionally patients are treated with a “one-size” fits all approachwhich typically includes a generic and heavy chemotherapy protocolregimen which is delivered to the entire body and designed to provide abalance between enough poison to kill the cancerous tissue withoutkilling all of the healthy tissue. High doses and multiple exposures toradiation are also typically used and delivered by products such as theGamma Knife and Cyber Knife. However, such invasive treatment regimensare often nothing more than a series of “experiments” on the patient inan effort to find an effective treatment plan. Accordingly the patientmust be monitored to ascertain the effectiveness of the generictherapeutic regimen and continuous modification and tweaking of thetreatment regime is performed based upon the positive or negativeresults of each of the previous successes or failures while attemptingto balance the sparing of healthy tissues and poisoning effect of thetreatment process on the whole patient. Such a treatment regimeeffectively results in the patient being a guinea pig until an effectivetreatment regime is achieved to manage the disease or in most cases thepatient dies from the disease. Unfortunately, in the case of braincancers, the patient often succumbs to the disease before an effectivetreatment regime is achieved. Regardless of these heroic clinicalefforts that are very biologically caustic to the patient, rarely areany of the current treatment paradigm curative. In fact, since patientsdiagnosed with brain cancers often do not typically live beyond 9-14months after initial diagnosis of the disease, long term clinicalimplications of whole body chemo or target directed radiation therapyare unknown in these patients and may be detrimental if the patientlived long enough for the true impact to be understood.

In addition, as many current treatment regimens involve deliveringchemotherapy through the bloodstream. However, the blood-brain barrier,which serves to separate circulating blood from the brain extracellularfluid in the central nervous system (CNS), creates additional challengesto delivering therapeutic agents to specific regions of the brainthrough the bloodstream. More specifically, the blood-brain barrieractually functions in a neuroprotective role. Thus the blood-brainbarrier can hinder delivery of therapeutic agents to the brain.Therapeutic molecules and antibodies that might otherwise be effectivein therapy do not cross the blood brain barrier in adequate amounts.

To overcome the treatment issues associated with the blood brainbarrier, mechanical opening of the blood brain barrier has beenproposed. In addition, use of smaller particles (i.e., nano-particles)have been proposed, whereby the smaller particles are sized to passthrough the blood brain barrier, then are attempted to be recombined toform a larger and more effective therapeutic molecule. Other means tobreach the blood brain barrier include delivering chemicals designed totemporarily open up the blood brain barrier to allow for a period oftime that larger molecules at therapeutic levels may pass across it.Once across the blood brain barrier, the therapeutic treatment muststill get to the diseased tissue, resulting in poisoning healthy tissue,as well as diseased tissue.

Accordingly, there exists a need for effective treatment regimes thatovercomes the challenges created by the blood brain barrier, whileproviding targeted treatment to the diseased tissue rather than healthyand diseased tissue.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments of the present disclosure will now be described ingreater detail with reference to the attached figures, in which:

FIGS. 1A-1C illustrate a prior art surgical access system.

FIG. 2 is a perspective cross-sectional view of an exemplary arrangementof a surgical access assembly.

FIG. 3 is a perspective view of an outer sheath of the surgical accessassembly of FIG. 2.

FIG. 4A is a side elevational view of the outer sheath of FIG. 3.

FIG. 4B is an enlarged cross-sectional view of a portion of the distalend of the outer sheath of FIG. 4A.

FIG. 4C is an enlarged cross-sectional view of a portion of analternative embodiment of the distal end of the outer sheath of FIG. 4A.

FIG. 5 is an end view of outer sheath of FIG. 3.

FIG. 6A is an elevational view of an alternative embodiment of an outersheath.

FIG. 6B is an end view of the outer sheath of FIG. 6A.

FIG. 7A is a perspective view of an obturator assembly of the surgicalaccess assembly of FIG. 2.

FIG. 7B is an enlarged view of an end face of the obturator assemblytaken from area 7B of FIG. 7A.

FIG. 8A is a top view of the obturator assembly of FIG. 7A.

FIG. 8B is an enlarged view of a distal end of the obturator assemblytaken from area 8B of FIG. 8A.

FIG. 8C is an alternative embodiment of the distal end of the obturatorassembly taken from area 8B of FIG. 8A.

FIG. 8D is an alternative embodiment of the distal end of the obturatorassembly taken from area 8B of FIG. 8A.

FIG. 9A is a side elevational view of the obturator assembly of FIG. 7A.

FIG. 9B is an enlarged view of a portion of the obturator assembly takenfrom area 9B of FIG. 9A.

FIG. 10 is an end view of the obturator assembly of FIG. 7A.

FIG. 11A is a perspective view of an illuminating ring that operativelyconnects to an outer sheath of the surgical access assembly.

FIG. 11B is a side view of the illuminating ring of FIG. 11A.

FIG. 11C is a top view of the illuminating ring of FIG. 11A.

FIG. 11D is a bottom plan view of the illuminating ring of FIG. 11A.

FIG. 11E is a cross-sectional view of an exemplary arrangement of alighting arrangement for the illuminating of FIG. 11A.

FIG. 11F is a plan view of a circuit board for use with the illuminatingring of 11A.

FIG. 11G is an exemplary electrical schematic for use with theilluminating ring of FIG. 11A.

FIG. 12 illustrates the illuminating ring of FIG. 11A assembled to anexemplary embodiment of the outer sheath.

FIG. 13 is a flow chart illustrating a process flow using the surgicalaccess assembly.

FIG. 14A-14B are images of a brain illustrating an area of interest,taken using an imaging modality.

FIG. 15 is an image taken of the brain shown in FIGS. 14A-14B,illustrating various critical structures, such as fiber tracts andfascicles of the brain.

FIG. 16A is an alternative embodiment of an obturator with an imagingdevice operatively connected thereto.

FIG. 16B is a partially exploded view of an enlarged cross-sectionalview of the proximal end of the obturator and post.

FIG. 16C is an alternative arrangement of a coil sensor for use with anobturator.

FIG. 16D is an end view of the coil sensor mounted on the post of FIG.16C.

FIG. 17A is an elevational view of the surgical access system, while theobturator is being withdrawn from the outer sheath.

FIG. 17B is an elevational view of the surgical access system with theouter sheath in place within the brain.

FIG. 18 is a perspective view of an exemplary surgical device used forcytoreduction.

FIG. 19A is an elevational view of an exemplary manipulation member.

FIG. 19B is an elevational view of an alternative manipulation member.

FIG. 20 is a partial perspective view of an exemplary delivery sleevethat may be used with a surgical device.

FIG. 21A is an exemplary arrangement for a therapy delivery device.

FIG. 21B is an alternative arrangement of the therapy delivery device ofFIG. 21A.

DETAILED DESCRIPTION

Referring now to the discussion that follows and also to the drawings,illustrative approaches to the disclosed assemblies and methods areshown in detail. Although the drawings represent some possibleapproaches, the drawings are not necessarily to scale and certainfeatures may be exaggerated, removed, or partially sectioned to betterillustrate and explain the present disclosure. Further, the descriptionsset forth herein are not intended to be exhaustive or otherwise limit orrestrict the claims to the precise forms and configurations shown in thedrawings and disclosed in the following detailed description.

Described herein is surgical access assembly, various components for usein same, and a method of using the surgical access assembly. Thecomponents disclosed herein provide surgeons with an enhanced ability tominimize trauma to the patient, while providing efficient improvedminimally invasive surgical techniques, such as, for example, duringintracranial surgical techniques. The components disclosed herein mayfurther be used for application of targeted and effective treatmentregimens.

Referring to FIG. 2, a perspective cross-sectional view of a surgicalaccess assembly 100 is shown. In one exemplary arrangement, surgicalaccess assembly 100 comprises a hollow outer sheath 102 and aselectively removable obturator 104. As best seen in FIG. 2, obturator104 is configured with a length that is longer than a length of outersheath 102 such that a distal end 106 of obturator 104 protrudes apredetermined distance from a distal end 108 outer sheath 102, as willbe discussed below in greater detail.

A locking member 110 may also be provided. Locking member 100 isconfigured to operatively retain a separate navigation member 112 (shownin phantom) within obturator 104, as will be discussed in greater detailbelow. A retaining member 114 may be secured within a portion ofobturator 104 to prevent locking member 110 from being completelydisengaged from obturator 104.

Referring now to FIGS. 3-5, outer sheath 102 will be described ingreater detail. Outer sheath 102 is defined by distal end 108 and aproximal end 116 and includes a generally hollow body portion 118 and agrip portion 120. In one exemplary arrangement, grip portion 120 isconfigured as a ring, as illustrated in the drawings. However, it isunderstood that grip portion 120 need not be configured as a ring. Forease of explanation, grip portion 120 will be referred to hereinafter asgrip ring 120. Grip ring 120 is fixedly secured to body portion 118 atproximal end 116. In one exemplary arrangement, body portion 118 isconstructed of a clear biocompatible material that permits viewing ofnormal tissue, abnormal tissue, as well as critical structures that aredisposed outside of body portion 118 when outer sheath 102 is disposedwithin such tissue. In one exemplary arrangement, outer sheath 102 isconstructed of polycarbonate, though other biocompatible materials maybe employed, including resins.

In one exemplary configuration, an imaging mechanism may be incorporatedinto outer sheath 102 that would permit visualization of tumors,vessels, fiber tracks, fascicles and even healthy tissue, in real-time.Indeed, as will be explained in further detail below, the imagingmechanism will enable physiological functional imaging to provideinformation about the characteristics of the cortical fiber tracks to bevisible, be visible, thereby enabling a user to separate and park suchfibers on either side of outer sheath 102 rather than cutting,stretching and potentially damaging such fibers while gaining access toa desired location within the brain. Further, as will be explained infurther detail below, the imaging mechanism may also enable the surgeonto have real-time information about the fiber tract and fasciclelocation, after placement of outer sheath 104, and during abnormalityresection procedure therethrough. In addition to white matter tractimaging, mapping of the characteristics of the cerebral blood flow maybe obtained.

In one exemplary embodiment, the imaging mechanism may be an ultrasoundprobe incorporated into outer sheath 102. For example, outer sheath 102may be provided with one or more channels within the wall that definesouter sheath 102 that are configured with one or more small diameterultrasound probes. In another arrangement, a single ultrasound probethat is configured to be received within outer sheath 102 may beprovided. In yet another embodiment, a low field MRI probe may beselectively placed in outer sheath 102 to provide enhanced imaging. Inyet another embodiment a low field MRI imaging coil may be molded intoor bonded into outer sheath 102. In still another exemplary arrangement,the probe may be an optical coherent tomography (OCT) imaging orspectroscopy.

Distal end 108 of outer sheath 102 may be configured with a taperedportion 130 that extends towards a center axis A-A of outer sheath 102to a distal edge 132 that surrounds an opening 134 in distal end 108 ofouter sheath 102. Tapered portion 130 serves to ease the transitionbetween outer sheath 102 and a distal tip portion 172, without drag,trauma or coring of tissue from a diameter that defines a body portion168 of obturator 104 to a diameter that defines body portion 118 ofouter sheath 102. In one exemplary configuration, distal end 108 may beconfigured with a radius or other configuration so as to create asmooth/atraumatic transition of the brain tissue when surgical accessassembly 100 is inserted into the brain.

For example, as best seen in FIG. 4B, distal edge 132 is configured soas to be non-sharpened and radiused. In one exemplary arrangement,distal edge 132 is configured as a 0.3 mm diameter radiused rim. Taperedportion 130 and radiused distal tip 132 cooperates with obturator 104 toatraumatically move tissue, as well as various structures within thebrain, including white matter, away from outer sheath 102 withoutcutting tissue or such structures. Indeed, unlike prior art devices thatinclude either a blunt tip distal end or a tapered leading edge such asthat shown in FIG. 1C, radiused distal tip 132 cooperates with taperedportion 130 and obturator 104 to prevent bruising and damage to varioustissue. More specifically, this configuration facilitates entry of outersheath 102 into delicate tissue, but without cutting such delicatetissue. Insertion of surgical access assembly 100 will be explained infurther detail below.

Body portion 118 may further be provided with a plurality of spacedapart indicators 136. Indicators 136 generally extend about thecircumference of body portion 118 and each may further incorporate asecondary indicator 138 that visually illustrates a predeterminedlocation on body portion 118, as shown in FIG. 3. While FIG. 3illustrates four indicators 136, it is understood that body portion 118may be provided in a variety of lengths and that any number ofindicators 136 may be provided. Body portion 118 may also be providedwith a longitudinal indicator 140. More specifically, as best seen inFIG. 4A, longitudinal indicator 140 extends from proximal end 116 todistal end 108. Indicators 136, 138 and 140 may be printed onto eitheran internal or external surface of body portion 118 with an imagingvisible ink such as, for example ink containing fluro-deoxyglucose(FDG), Technicium 99, Gadolinium, titanium dust, barium sulfate, acombination of the above or other suitable imaging material. Indicators136 and 138 provide a reference point for the operator of system 100, asstructures may be visible through body portion 118. Indicator 136, 138and 140 may also be configured to be visible under MRI, CT, PET, or anyother suitable imaging modality to enable easy identification of areasof interest. In one alternative embodiment, indicators 136, 138 and/or140 may be etched or printed onto body portion 118, either on theinternal or external surface of body portion 118.

Details of grip ring 120 are best seen in FIG. 5. Grip ring 120 isgenerally configured as a flange member 142 defined by an outerperiphery 144 and an inner opening 146. Inner opening 146 may be sizedto generally correspond to the diameter of a lumen 148 defined by bodyportion 118. Outer periphery 144 is sized to have a diameter that islarger than lumen 148 of body portion 26. Flange member 142 may furtherbe provided with one or more small openings 150 that are disposedtherein. In one exemplary arrangement, a plurality of small openings 150are provided that are spaced generally equi-distantly about inneropening 146. Small openings 150 will be described in further detailbelow. Outer periphery 144 may further be provided with a texturedsurface 152 to provide for ease of gripping outer sheath 102. Forexample, in one exemplary arrangement, textured surface 152 comprises aplurality of alternating ridges 154 and grooves 156. However, it isunderstood that other textured surfaces may be employed.

Disposed on a proximal end surface 158 of flange member 142, analignment feature 160 may be employed. Alignment feature 160 is used toindicate the location of longitudinal indicator 140 when outer sheath102 is positioned within the brain. Alignment feature 160 will bediscussed below in greater detail.

An alternative embodiment of outer sheath 202 is shown in FIGS. 6A-6B.Outer sheath 202 is similar to outer sheath 102 in that it is defined bya distal end 208, a proximal end 216 and a body portion 218. A distaledge 232 is generally configured to be similar as distal tip 132. A gripring 220 is fixedly secured to body portion 218.

Grip ring 220 also includes a textured surface 252. Grip ring 220further includes a locating member 262. Locating member 262 isconfigured to operatively connect an illumination ring (best seen inFIG. 11A) 300 to outer sheath 102. As may be seen, in one exemplaryconfiguration, locating member 262 extends outwardly from outerperiphery 244 of grip ring 220. Locating member 262 may also serve as analignment feature for indicating the location of longitudinal indicator240. Alternatively, a separate alignment feature 260 may be provided.For example, in FIG. 6B, alignment feature 260 is positioned adjacentlocating member 262.

Body portion 218 may also be provided with indicators 34, 36, and 38 toassist in locating outer sheath 202 in operation. However, in anotheralternative arrangement, body portion 218 may be provided withindicators 264 that produce a signal void or minimal artifact undercertain imaging modalities. In one specific arrangement, indicators 264may be configured as small holes that are spaced apart at predetermineddistances, as shown in FIG. 6A. In yet another alternative arrangement,indicators 264 may be configured as non-through divots. In still afurther alternative arrangement, indicators 264 may be configured as alongitudinal groove (not shown) on either the internal or externalsurface of body portion 218.

Referring to FIGS. 7-10, obturator 104 will now be described. Obturator104 is defined by distal end 106, a proximal end 166, a body portion 168and a handle portion 170. Distal end 106 is configured with a generallyconical shaped distal tip portion 172 that tapers to a tip member 174 toprovide atraumatic dilation of tissue. In one exemplary arrangement, tipportion 172 tapers toward a closed tip member 174 so as to preventcoring of tissue as obturator 104 is inserted into the brain.

There are a number of variables that play the selection of the angle αthat defines the taper of tip portion 172. These variables include thesize of an outer diameter D1 of obturator 104, the desired length thatdistal tip portion 172 extends from body portion 168, and the desiredoffset for a distal tip of navigation member 112 and tip member 174.More specifically, it is contemplated that surgical access assembly 100will be provided as part of a kit that may include multiple sized outersheaths 102 and obturators 104, to provide the surgeon with a choice ofdifferent diameter sizes and lengths so as to provide flexibility foraccessing areas of interest within the brain. However, to insure thatthe distal tip 174 is determinable regardless of which size diameter D1of obturator 104 is used, taper angle α may be selectively adjusted. Forembodiments that utilize navigation member 112 that positions a distalend thereof at a set position within obturator 104 (as will be explainedin further detail below), to maintain an identical offset length betweenthe distal end of navigation member 112 and distal tip 174 in differentdiameter D1 sized obturators 104, taper angle α will need to beincreased, as diameter D1 increases.

For example, if diameter D1 of obturator 104 is 13.5 mm, an exemplaryangle α may be 45.5° to provide effective atraumatic dilation, as wellas a determinable distal tip 174 location. However, if diameter D1 ofobturator 104 is 15.5 mm, an exemplary angle α′ may be 52.8°.

As best seen in FIG. 8B, distal tip 174 is configured to be radiusedsuch that tip member 174 is rounded, and neither blunt, nor sharp. Morespecifically, tip member 174 is configured so as not to have any flatportions which during insertion can stretch or even tear the delicatetissues such as the vessels, fiber tracts and fascicles found in thebrain. Further, because tip member 174 is closed, damage of suchdelicate tissues and fascicles are also avoided. In one exemplaryembodiment, tip member 174 is configured with a 0.5 mm radius. As willbe explained in further detail below, the configuration of tip member174 is designed to gently displace and move the tissue into which it isinserted; i.e., atraumatically dilate the tissue to allow forintroduction in to an intra-fascilar and para-fascilar manner, asopposed to cutting tissue as surgical access assembly 100 is insertedinto the tissue.

Handle portion 170 is positioned at proximal end 166 of obturator 104.As best seen in FIGS. 7B, 8A and 9A, handle portion 170 comprises a stopmember 176 and a grip member 178. Stop member 176 is positioned distallyof grip member 178 and, as best seen in FIG. 8A, is configured to have awidth W1 that is greater than a diameter D1 of body portion 168, as wellas a diameter D2 of outer sheath 102 (shown in FIG. 4A). Grip member 178is configured with a width W2 that is greater than the width W1 of stopmember 176, thereby providing a step-like configuration. Stop member 176further defines an engagement surface 177 that is axially spaced from adistal surface 179 of grip member 178.

In one exemplary arrangement, handle portion 170 is configured with agenerally planar surface 180, as best seen in FIGS. 7A-7B and FIG. 10.Planar surface 180 is configured with a receiving aperture 182 that isconfigured to receive locking member 110. In one exemplary arrangement,receiving aperture 182 is threaded. As best seen in FIGS. 2, 7B, and 8A,disposed within receiving aperture 182 is an engagement opening 184.Engagement opening 184 is in communication with a channel 186 (seen inphantom in FIGS. 8A and 9A) that extends at least partially thoroughhandle portion 170. After locking member 110 is at least partiallyengaged within receiving aperture 182, retaining member 114 (FIG. 2) ispositioned within channel 186. Because engagement opening 184 opens intoreceiving aperture 182, a portion of retaining member 114 extends acrossa portion of receiving aperture 182 such that locking member 110 isprevented from being entirely withdrawn from receiving aperture 182. Forexample, locking member 110 is illustrated as having threads thatcooperate with corresponding internal threads in receiving aperture 182.Retaining member 114 is positioned within channel 186 so as to extendabove the threads of locking member 110 such as locking member 110 isbeing removed from receiving aperture 182, threads come into contactretaining member 114, thereby preventing complete removal of lockingmember 110 from handle portion 170.

An access opening 188 is formed through proximal end 166. Access opening188 extends through handle portion 170. In one exemplary arrangement,access opening 188 may be provided with an inwardly extending chamfer189 that tapers toward access opening 188. Chamfer 189 provides aself-directing feature for inserting navigation member 112 into accessopening 188. Access opening 188 is in communication with a first channelsegment 191 that extends through handle portion 170 and into bodyportion 168.

As seen in FIG. 8D, obturator 104 may further be configured to receive aviewing member 167 operatively connected thereto. More specifically,conical tip portion 172 may be configured with one or more viewingwindows 169 that are oriented to be flush with the surface of conicaltip portion 172. Viewing windows 169 are in communication with a viewingmember channel 171 that may selectively receive a viewing member suchas, for example, a fiber optic cable or an ultrasound probe. The viewingmember may be in addition to the use of navigation member, or in placethereof. The viewing member permits the surgeon to observe, in real-time(i.e., during insertion), surrounding tissue and eloquent tissuestructures so as to minimize trauma during insertion.

Body portion 168 extends between distal end 106 and proximal end 166.Body portion 168 includes one or more elongated void areas 190. Voidareas 190 serve to reduce weight of obturator 104, thereby makingobturator 104 easier to manipulate during surgical procedures. Voidareas 190 also facilitate sterilization of obturator 104 by moistureretention within body portion 168 of obturator 104. Further, void areas190 also provide venting, thereby preventing a vacuum from beinggenerated as obturator 104 is being withdrawn from outer sheath 102during operation.

Void areas 190 are separated by web portions 192 that extend axiallythrough a portion of the length of body portion 168. Disposed on webportions 192 of body portion 168 are one or more indicators 194.Indicators 194 may include spaced apart hash marks (designated as 194A)that cooperate with an imaging modality to provide information, inreal-time, concerning the location of obturator 104 relative to varioustissue, critical structures, and fascicles within the brain, whileobturator 104 is positioned within tissue. Indicators 194 also assistwith providing information to regarding the relative positions betweenobturator 104 and outer sheath 102. Indicators 194 produce a signal voidor minimal artifact under certain imaging modalities.

Body portion 168 may further include one or more cross webs 196. Crosswebs 196 are oriented transverse to web portions 192 and connect webportions 192 together. In one exemplary arrangement, body portion 168includes at least one cross web 196 that operatively defines the outerdiameter D2 of body portion 168. Diameter D2 is sized to fit withinlumen 148 of outer sheath 102 such that obturator 104 and outer sheath102 may be selectively slid relative to one another. However, diameterD2 is also sized to minimize or even eliminate any gaps between an innersurface of outer sheath 102 and an outer surface of obturator 104. Inthe exemplary arrangement shown in FIG. 7-9, three cross webs 196A, 196Band 196C are provided. A first cross web 196A is connected to distal tipportion 172, while second cross web 196B is spaced proximally from firstcross web 196A and separated by a void area 193. Third cross web 196C isseparated from second cross web 196B by void areas 192 and is positioneddistal from first stop member 176 of handle portion 170. Cross webs 196serve to provide for structural integrity of obturator 104, as well asimproved rigidity.

In one exemplary arrangement, one or more of cross webs 196 may furtherbe provided with an annular compensating protuberance 197 to accommodatefor slight manufacturing variations of the diameter of lumen 148 ofouter sheath 102. For example, as it is contemplated that outer sheath102 may be a component that is molded from a resin, a process which mayproduce such slight manufacturing variations. Compensating protuburance197 extends slightly radially outwardly from an outer surface ofobturator 104 and cooperates with lumen 148 of outer sheath 102 tocreate a friction fit between the outer surface of obturator 104 andlumen 148, due to the slight flexibility of the resin of outer sheath102. Use of compensating protuberance 197 thereby reducing the need formaintaining a high dimensional tolerance of outer sheath 102 inproduction.

In one embodiment, cross web 196B is provided with a second channelsegment 198 (shown in phantom) that extends there through. Secondchannel segment 198 is axially aligned with first channel segment 191and is configured to selectively receive navigation member 112. In oneexemplary arrangement, disposed in first cross web 196A is an inwardlyextending depression 199, as best seen in FIG. 9B. Depression 199 isconfigured in such a manner so as to align a distal tip of navigationmember 112 with distal end 108 of outer sheath 102, when outer sheath102 is assembled to obturator 104.

Referring to FIGS. 11A-11F, details of an optional illuminating ring 300will now be described. Illuminating ring 300 is generally defined by atop surface portion 302, a wall member 304. A circuit board 306 may alsobe provided. Top surface 302 includes at least one access opening 308therethrough that is configured to receive one or more surgicalinstruments, as will be described below in further detail. Additionalsmall openings 309 may be provided in top surface 302. One or more ofsmall openings 309 are configured to be aligned with small openings 150disposed on flange member 142. Wall member 304 extends from top surface302 so as to create an open cavity 310 within illuminating ring 300. Anouter surface of wall member 304 may be textured (not shown), similar togrip ring 120.

One or more light elements 312 that are supported by a portion ofilluminating ring 300. In one embodiment, shown in FIG. 11E, lights 312are fixedly mounted to top surface 304 so as to face inwardly towardopen cavity 310, adjacent access opening 308. Each light 312 iselectrically connected to a remote power source (not shown) by wires314. In one exemplary arrangement, wires 314 may be retained withinchannels formed in top surface 302 around access opening 308.

In an alternative arrangement (FIG. 11F), lights 312 may be incorporatedin a circuit board 306. Circuit board 306 is configured with an accessopening 316 that may be aligned with access opening 308 formed in topsurface 302. Further, circuit board 306 is also sized to be positionedwithin open cavity 310, and fixed thereto. In other words, in onearrangement, circuit board 306 is sized to have an outer diameter thatis smaller than an inner diameter defined by wall member 304. A wallopening 318 may be formed through a portion of either top surface 302 orwall member 304 to provide access for wires 320 to electrically connectcircuit board 306 to a power source. An example of wall opening 318 maybe seen in FIGS. 11B, 11D, and 11F. Circuit board 306 may be configuredsuch that there is a constant output of light when illuminating ring 300is turned on so that there is a steady state.

An exemplary circuit design 321 is depicted in FIG. 11G for circuitboard 306. In the exemplary configuration, circuit design 321 isconfigured to prevent flickering of lights 312 and/or prevent operationof less than all of the lights 312 during use of illuminating ring 300.More specifically, circuit design 321 is configured such that if onelight 312 burns out, or if batteries that supply power to circuit getlow, illuminating ring 300 will simply shut off and a replacementbattery pack (not shown) may be used.

In one exemplary arrangement, lights 312 are LED lights, although otherlight devices may be utilized. LED lights do not contributesignificantly to the weight of surgical access assembly 100, and alsodissipates a non-clinical significant amount of heat. Moreover, LEDlights can emit different combinations of colors/frequencies of lightthat may be incorporated to illuminating ring 300, to provide improvedvisualization of fluorescing dyes which allow for the differentiation oftissues.

Use of LED lights also allow for an endoscope to be used with surgicalaccess assembly 100, but without an accompanying fiber-optic lightsource. This arrangement significantly reduces a required overalloutside diameter of the endoscope, which improves the working spacewithin lumen 148 of outer sheath 102. More specifically, lumen 148 ofouter sheath 102 has more available working space, thereby providingincreased simultaneous use of multiple instrumentation, as well asimproved visualization. Further, because traditional endoscope devicesmust be attached to a supporting structure that is fixed to anintroducer cannula, the weight of such an assembly tends to pull on theintroducer cannula, in one direction. This action can compromise theplacement of the introducer cannula during the procedure and/or causetrauma to brain tissue. Thus, by incorporating illuminating ring 300 toouter sheath, such potential disadvantages may be avoided.

While illuminating ring 300 may be secured to grip ring 120 of outersheath 102 in any suitable manner, in one exemplary arrangement,illuminating ring 300 is provided with a selective locking arrangementto selectively fix illuminating ring 300 to grip ring 120. In oneexemplary arrangement, wall member 304 is provided with a lockingchannel 322, best seen in FIG. 11B. Locking channel 322 comprises wallopening 318 and that opens into a first channel segment 324, and asecond channel segment 326 that is in communication with first channelsegment 324. Wall opening 318 extends from a bottom surface 328 of wallmember 304. Second channel segment 326 is spaced upwardly from bottomsurface 328 of wall member 304 and is oriented at an angle from firstchannel segment 324. In one exemplary arrangement, second channelsegment 326 is oriented 90° from first channel segment 324.

Locking channel 322 cooperates with locating member 262 to selectivelysecure illuminating ring 300 to grip ring 120. More specifically,illuminating ring 300 is pushed down over grip ring 120 with locatingmember 262 entering wall opening 318. As illuminating ring 300 is pusheddownwardly, locating member 262 travels through first channel segment324. Once locating member 262 contacts a terminal end 330 of firstchannel segment 324, illuminating ring 300 is rotated relative to outersheath 102 such that locating member 262 moves into second channelsegment 326, thereby selectively locking illuminating ring 300 to outersheath 102, as shown in FIG. 12. Once connected, illuminating ring 300thereby provides a hands-free light source to illuminate lumen 148 ofouter sheath 102.

In one exemplary arrangement, certain segments of outer sheath 102 maybe frosted so as to reflect light to increase visualization within outersheath 102. For example, tapered portion 130 may be frosted. Similarly,the top of grip ring 120 may also be frosted.

Operation of surgical access assembly will be described in connectionwith a process flow 400 illustrated in FIG. 13. Generally speaking,before any surgical procedure is decided upon, a patient will firstpresent with symptoms or deficits requiring evaluation. Thus, the startof process flow 400 begins with a surgeon making a determination 402 ofthe cause of such neurological symptoms/deficits. Such a determinationmay be made through use of a variety of imaging modalities, including,but not limited to, MRI or CT imaging. The process then proceeds to step404.

If the determination from step 402 finds that a brain condition isfound, such as a tumor or hematoma, an additional determination isrequired. More specifically, a location of the brain condition isdetermined in step 404. If the imaging determines that an area ofinterest is located in the intra-axial/subcortical space, the processflow continues to step 406. However, if a brain condition is located inother, more easily accessible areas of the brain, the process flowstops.

As discussed above, any suitable imaging modality may be utilized todetermine if a brain condition exists, and if so, where that braincondition is located. FIGS. 14A and 14B illustrate examples of imagingresults from an MRI. More specifically, an area of interest 500, in thiscase a tumor, may be seen deep in the subcritical space.

Once area of interest 500 is located, at step 406 an additional imagingsequence is employed to determine the location of eloquent structuressuch as vessels and fiber tracts and the associated fascicles so as toplan the safest access route to the area of interest. Exemplaryarrangements for accomplishing this step include CT-Angiography and MRIwith Diffusion Tensor Imaging (DTI) sequences. DTI allows for thedetermination of directionality as well as the magnitude of waterdiffusion along the communication “wiring” pathways called fiber tractsand fascicles. This kind of MRI imaging can provide imaging to allow forthe estimation of potential damage to nerve fibers that connect theareas of the brain which can be affected by a stroke, for example, tobrain regions that are distant from it, and can also be used tovisualize white matter fibers in the brain and can map (trace image)subtle changes in the white matter associated with diseases such asmultiple sclerosis and epilepsy, as well as assessing diseases where thebrain's wiring is abnormal, such as schizophrenia, as well as tumorinvolvement.

Diffuse Tensor Tractography (DTT) may also be used. DTT allows fornoninvasive racking of neuronal fiber projections in a living humanbrain. White matter fiber trajectories are reconstructed throughout thebrain by tracking the direction of fastest diffusion, which is assumedto correspond to the longitudinal axis of the tract. Diffusion tensortractography provides insight into white matter integrity, fiberconnectivity, surgical planning, and patients' prognosis. Once theimaging information has been analyzed, the process then proceeds to step408.

Referring to FIG. 15, an example of DTI imaging of the brain shown inFIGS. 14A and 14B is depicted. A map of fascicles and other vessels areillustrated in FIG. 15, including major vessels 502 that are shownspread around area of interest 500. Such images provide the surgeon withvaluable information about potential avenues for access tracts to areaof interest 500.

In step 408, a plan for the operative trajectory is developed. Morespecifically, imaging information is used to plan (either manually orwith software) the access tract/pathway to achieve fiber tractinvolvement during access to the area of interest. In evaluating fibertract involvement from a potential access tract/pathway, considerationof fiber tract importance may be based on an individual patient'soccupational and personal needs and/or preference. Once a pathway hasbeen planned, the process proceeds to step 410.

In step 410, image data from the MRI/DTI and CT/CTA image sequenceobtained during step 406 is input into an intraoperative navigationsystem. Intraoperative navigation systems may be used to provide directvisualization of area of interest 500 in real time, as surgical accesssystem 100 is being positioned within the brain. The method thenproceeds to step 412

Once the procedure has been planned and the image data has been uploadedto a navigational system, step 412 requires that the appropriate sizedsurgical access assembly 100 is selected. First the appropriate size ofa craniotomy must be determined. Further, the present disclosurecontemplates that different diameter and length sizes of surgical accessassembly 100 may be employed, the size depending on the particularlocation of area of interest 500. Accordingly, step 412 requires thatthe surgeon select the appropriate length and diameter of surgicalaccess system 100 to be used, based on the physical and locationcharacteristics of the area of interest 500. Once surgical accessassembly 100 is selected, the process proceeds to step 414.

In step 414, the surgeon creates the craniotomy and Dural accessincision. The process then proceeds to step 416.

In step 416, the obturator 104 is inserted into outer sheath 102 untilgrip ring 120 abuts first stop member 176, as shown in, for example FIG.2. Navigation member 112 is then operatively connected to obturator 104.

As discussed above, various types of navigation members 112 may beemployed with surgical access assembly 100. In one exemplaryconfiguration, navigation member 112 is configured as a probe (as shownin FIG. 2). In this configuration, navigation member 112 is insertedthrough access opening 188 of grip member 178 until a distal tip 417 ofnavigation member 112 is deposited into depression 199 (see FIG. 9B).Depression 199 is formed so that distal tip 471 of navigation member 112is positioned within the same plane as distal tip 132 of outer sheath102, when obturator 102 and outer sheath 104 are assembled together asshown in FIG. 2. Locking member 110 may be tightened to fixedly retainnavigation member 112 within obturator 102. A portion of navigationmember 112 will extend proximally from grip member 178 and will beoperatively connected to a navigation system that includes a screen thatvisually illustrates the information obtained from the imagingsequences, along with the trajectory of surgical access system 100.Thus, with the navigation member 112 operatively connected to anavigation system, the position of distal tip 132 of outer sheath may beindicated, in real time, while surgical access system 100 is beingnavigated within a body.

In another configuration, the software operating the navigation systemmay further be provided with an offset dimension that corresponds to adistance D3 between distal tip 174 of obturator 104 and distal tip 132of outer sheath. In this arrangement, a dotted line may appear on thenavigation screen that indicates where distal tip 174 of obturator 104is located, in real-time.

Navigation member 112 may further be provided with image guidanceposition indicators, such as an array of reflectors of the type use inconnection with optical image guidance systems. The infrared reflectorsused with such a system are mounted to a handle of a probe-likenavigation member 112 in a customary triangular configuration calibratedto identify the tool to the image guidance system. Such imaging systemsare available, for example Medtronic Surgical Navigation Technologies(Denver, Colo.), Stryker (Kalamazoo, Mich.), and Radionics (BurlingtonMass.).

Typically, the positioning of the indicators is calibrated such that theimage guidance system can project an image of the tool onto a display ofimages of the patient's brain, such as MRI images used to plan surgery.Thus, as discussed above, as surgical access system 100 is inserted, thesurgeon can see the relative position of system 100 relative to thestructures of the brain as reflected on images, and particularly withrespect to the target tissue.

Other guidance systems, such as magnetic or electromagnetic or radiotransmitting systems may also be used, and the illustration of infraredreflectors and discussion of optical image guidance systems areexemplary only and are not intended to be limiting. In addition, whilethe exemplary method has been described in connection with superimposingan image of surgical access system 100 onto a pre-operative image, it iscontemplated that real-time imaging capability may be utilized and thatthe image of surgical access system 100 may then be shown in relation tothe surrounding tissue structures on a real time image.

In another exemplary configuration, an RFID chip may be embedded inobturator 104 that operatively communicates information to a navigationsystem or other surgical system about the specific attributes, such as,but not limited to, length and diameter. This information may be used tofacilitate placement with the navigation system or other systems forinformation display or trajectory and location calculations duringplacement of obturator 104.

In yet another exemplary arrangement, as shown in FIGS. 16A-16B, analternative embodiment of an obturator 504 may be used, wherein theobturator 504 is configured with a post 512 that is configured tooperatively attach a navigation array. Post 512 may be detachably orpermanently connected to grip member 578 of obturator 104. For example,as shown in FIG. 16A, post 512 is configured to be selectivelydetachable and may be used to capture a small coil 513 for Mill trackingof surgical access assembly 100. A portion of post 512 may be threadedand an access opening 588 formed in a proximal face of grip member 578have be provided with corresponding threads (not shown) so as to affixpost 512 to obturator 504. Other manners of selectively affixing post512 to obturator 504 are also contemplated, including, but not limitedto, a locking member 110 arrangement similar that shown in FIG. 2. Asalso discussed, post 512 need not be selectively detachable. Indeed, itis contemplated that post 512 may be permanently affixed to obturator504, in any suitable manner, whereby the navigation array may be securedto post 512. In yet another alternative arrangement, obturator 504 maybe configured such that a post, which is an element of the array itself,may be attached.

In still a further alternative arrangement, referring to FIGS. 16C-16D,a coil sensor 513′ may be configured to be disposed about an outerperiphery of post 512. In this arrangement, coil sensor 513′ is slid orotherwise mounted to post 512 such that when post 512 is operativelyattached to obturator 504 coil sensor 513′ is captured between a portionof grip member 578 and a proximal end portion 514. A connecting wire 516operatively attaches coil sensor 513′ to an image position console 518.

Once surgical access assembly 100 is assembled and operatively connectedto a navigational system, the process then proceeds to step 418, inwhich surgical access assembly 100 is navigated to area of interest 500.In one exemplary arrangement, distal tip 178 of obturator 104 isdirected to a furthermost outer margin of area of interest 500. Morespecifically, referring to FIG. 14B, for example, surgical accessassembly 100 is directed along a trajectory T that extends through areaof interest 500 to a location 501 that may be positioned within themargins of area of interest 500 or even slightly beyond the margin.

Due to the tapered configuration and closed, radiused distal tip 174 ofobturator 104, as well as the radiused distal tip 132 of outer sheath102, as surgical access assembly 100 is inserted into the brain andnavigated to area of interest 500, tissue is gently pushed to eitherside of surgical access assembly 100, so as to atraumatically dilatetissue, while minimizing trauma to the tissue. Further, because surgicalaccess assembly 100 is operatively connected to navigation member 112,as surgical access assembly 100 is being inserted into the brain tissue,navigation member 112 may cooperate with an imaging modality toproviding real-time information concerning fiber tact in trajectory T,thereby allowing the surgeon to minimize fiber tract compromise ordamage during insertion of surgical access assembly 100. Once surgicalaccess assembly 100 is positioned at area of interest 500, the processproceeds to step 420.

As step 420, navigation member 112 removed from or detached fromsurgical access assembly 100. The process then proceeds to step 422.

Once navigation member 112 is removed, outer sheath 102 is thenoperatively positioned with respect to area of interest 500. Morespecifically, as shown in FIG. 17A, outer sheath 102 is decanted withrespect to obturator 104 such that distal end 108 of outer sheath 102 ismoved toward distal end 106 of obturator 104, as indicated by arrow M.This action is accomplished by grasping grip ring 120 with one handwhile maintaining obturator 104 stationary, such, for example, graspinggrip member 178 with another hand. Grip ring 120 may be gently rotatedand/or swiveled with respect to a central axis of obturator 104 toenable outer sheath 102 to be moved distally with respect to obturator104. First stop member 176 aids in gripping and manipulating outersheath 102, in that a gap 423 (see FIG. 2) is created between endsurface 158 and a distal end surface of grip member 178. Outer sheath102 is decanted until grip ring 120 aligns with indicator 194A (see FIG.7A). Indicator 194A is spaced from first stop member 176 a distance thatgenerally corresponds to the length of distal tip portion 172 ofobturator 104. Accordingly, when grip ring 120 is aligned with indicator194A, distal end 108 of outer sheath 102 is aligned tip member 174 ofobturator 104. Moreover, outer sheath 102 is positioned within area ofinterest 500. The process then proceeds to step 424.

In step 424, once outer sheath 102 is appropriately positioned,obturator 104 is then removed from outer sheath 102, as shown in FIG.17B. More specifically, outer sheath 102 is maintained to be relativelystationary at area of interest 500, and obturator 104 is moved in aproximal direction until fully removed from outer sheath 102. Thisaction results in outer sheath 102 forming a pathway to area of interest500; a pathway that not only breaches the blood brain barrier, but alsoprovides direct access to the area of interest in the patient. Theprocess then proceeds to step 426.

In step 426, outer sheath 102 is then secured in place so as to preventcranial pressure from pushing outer sheath 102 out of the brain tissue.In one exemplary arrangement, a securing member may be utilized withsmall openings 150 on grip ring 120 to temporarily secure outer sheath102. For instances where illuminating ring 300 is used with surgicalaccess assembly 100, small openings 309 in illuminating ring 300 alignwith small openings 150 of grip ring. Accordingly, securing members mayalso be utilized with small openings 309. However, the securing membermay be secured so as to permit a limited degree of movement, as will bediscussed below, so as to result in a floating system that permitsselective repositioning. Suitable securing members include, but are notlimited to, bridle sutures, flexible bands with retaining hooks, or evenrepositionable retractor arms. Once outer sheath 102 is secured, theprocess then proceeds to step 428.

In step 428, debulking area of interest 500 may be conducted.Traditionally, a patient is given medication, such as, for example,Mannitol, before an intracranial operation to reduce intracranialpressure (ICP) of the brain prior to the surgery. Indeed, ICP is oftenexperienced by patients due to the natural response of the craniotiomyand/or the present of an abnormality within the brain. The presentinventors have found that it may be advantageous to omit or minimize theuse of medication for reducing ICP. More specifically, by not reducingICP, because the brain tends to occupy the available space within theskull, after obturator 104 is removed from outer sheath 102, the targettissue may have a tendency to flow into, and present itself into theopen distal end 108 of outer sheath 102, due to the cranial pressure.Area of interest 500 may actually move into outer sheath 102 on its own,thereby assisting in the delivery and minimizing manipulation requiredof outer sheath 102 during the process.

It is contemplated that a wide range of surgical devices may be insertedinto outer sheath 102 to remove tissue abnormalities. In one exemplaryarrangement, it is contemplated that outer sheath 102 may have an innerdiameter up to approximately 20 mm, to allow multiple instruments, suchas graspers, dissectors, scissors, cautery and suction instruments to beinserted through outer sheath 102 to perform surgery.

One exemplary surgical device that may be used is the NICO MYRIAD®manufactured and distributed by Nico Corporation of Indianapolis, Ind.Referring to FIG. 18, an exemplary surgical cutting device 640 is shown,such as that disclosed in co-pending, and co-owned with the assignee ofthe present application, U.S. patent application Ser. No. 12/389,447,the contents of which are incorporated by reference in its entirety.Surgical cutting device 640 includes a handpiece 642 and a cuttingelement that includes an outer cannula 644 and an inner cannula (notshown). In one exemplary configuration, handpiece 642 is configured witha generally cylindrical shape. Handpiece 642 may be sized and shaped tobe grasped with a single hand. Handpiece 642 also includes a lowerhousing 650 comprising a proximal section 646 and a distal section 648.A front housing section 655 may be connected to a cam housing positionedin distal section 648. An upper housing 652 is also provided. Thecutting element is mounted to upper housing 652 and may be fluidlyconnected to a tissue collector 658. In one exemplary arrangement,tissue collector 658 may be operatively connected directly to upperhousing 652. Alternatively, tissue collector 658 may be remotelyconnected to the cutting element by appropriate tubing. A vacuum line(not shown) may be connected to a proximal end of tissue collector 658to direct tissue into the cutting element, as well as to deliver severedtissue to tissue collector 658. A rotation dial 660 for selectivelyrotating the outer cannula 644 with respect to handpiece 642 is alsomounted to upper housing 652, to provide controlled cutting action.

Use of surgical device 640 is advantageous in that space is limited toeffectuate tissue debulking, such that use of traditional surgicalscissors may be challenging, especially when other instruments areinserted into outer sheath 102 simultaneously. Moreover, fibrosity of atumor may present challenges for the use traditional suction debulkingdevices. Traditional graspers operate by tearing tissue of interest.However, the tearing action may become problematic if vessels orfascicles are too close to the tissue being torn in that such vessels orfascicles may also be torn.

In step 428, as area of interest 500 is cytoreductively debulked, it maybecome necessary to reposition or move outer sheath 102. Ifrepositioning is necessary, the process moves to step 432. To that end,in one exemplary arrangement, manipulation members may be provided.Examples of manipulation members 700 and 700′ are illustrated in FIGS.19A-19B. Manipulation member 700 comprises a handle member 702 thatsupports an armature 704, and a hook element 706 that extends fromarmature 704. Hook element 706 is sized to fit within small openings 150and 309 disposed within grip ring 120 and illuminating ring 300,respectively. In operation, hook element 706 is engaged with a smallopening 150/309 and handle member 702 is used to gently push or pullouter sheath 102. Because outer sheath 102 is only loosely secured,outer sheath 102 may be selectively moved slightly for improvedvisualization or to access tissue. After outer sheath 102 has beenrepositioned, or if repositioning of outer sheath 102 is not necessary,the process moves to step 434, and cytoreduction of area of interest 500continues.

In an alternative arrangement, manipulation member 700′ may be securedto a flexible holder member 710. Manipulation member 700′ comprises anarmature 712 that carries a hook element 714 and an engagement portion716. Engagement portion 716 operatively engages holder member 710 so asto fixedly secure manipulation member 700′ to holder member 710, therebyfreeing a surgeon's hand, once outer sheath 102 is positioned. It isunderstood that multiple manipulation members 700/700′ may be utilizedto permit a surgeon to selectively push or pull outer sheath 102.

Outer sheath 102 is configured such that multiple instruments may beinserted simultaneously therewithin, thereby increasing the speed andsafety of surgical procedures. In one exemplary arrangement, anendoscope may be partially inserted and held to one side of outer sheath102, to provide an image of area of interest 500 to a monitor, while asurgical instrument, such as surgical instrument 640 is also insertedwithin outer sheath 102. Illuminating ring 300 may also be used, withthe endoscope and the surgical instrument being inserted through accessopening 308 that aligns with opening 146 of grip ring 120. Becauseilluminating ring 300 provides the necessary light for outer sheath 102,a relatively small diameter endoscope may be use, thereby increasing theavailable space within outer sheath 102 for other surgical instruments.In another exemplary configuration, the surgeon may have both a surgicalinstrument and a cautery instrument simultaneously inserted into outersheath 102, thereby permitting the surgeon to cauterized vessels thatare encountered during the procedure.

In another exemplary arrangement, during the procedure, fluorescing dyemay be introduced into the patient, either before surgery or during thesurgery. One such dye is Gliolan (5-Aminolevulinic Acid), however othersuitable dyes may also be used. The fluorescing dye may be introduced byany suitable methods, including, but not limited to, injecting thepatient with the dye, providing the dye orally to the patient prior tosurgery, or even injecting the dye in situ through outer sheath 102. Inone exemplary arrangement, the dye is configured to bond to proteins ofabnormal cells such that the cells are visually distinguishable fromhealthy cells. With this visual indication of healthy vs. abnormaltissue, the surgical instrument may be more efficiently used to resectabnormal tissue. In other embodiments, light delivered through outersheath 102 has a predetermined wavelength that is configured to interactwith the dye to illuminate or fluoresce abnormal tissue. For example,illumination cap 300 may be provided with LED lights of a preselectedwavelength that operatively interacts with a preselected dye toilluminate abnormal tissue and assist with differentiating healthytissue from diseased tissue.

In another exemplary configuration, a light probe or fiber optic bundle(not shown) may be inserted into outer sheath 102 to assist withdifferentiation between healthy tissue and abnormal tissue. In onearrangement, the probe/bundle is simply inserted into outer sheath 102as a separate element, along with a surgical device. The probe/bundle isoperatively connected to a console such that the reflected light isdelivered to the console. A sensor in the console (i.e., the sensor isremotely located from the point of detection, receives the reflectedlight to trigger a signal to the user based on predetermined parameters.In other words, the natural florescence of the tissue is then reflectedback to the console to inform the user whether or not the tissue isdiseased or abnormal.

In another exemplary configuration, the surgical device may be furtherprovided with a delivery sleeve 800 that mounts to surgical device 640,and example of which may be found in FIG. 20. Various embodiments ofdelivery sleeve 800 may be found in co-pending, and co-owned with theassignee of the present application, U.S. patent application Ser. No.13/269,339, the contents of which are incorporated by reference in itsentirety. As may be seen in FIG. 20, delivery sleeve 800 generallyincludes at least two lumens, a first lumen 802 which is configured toreceive outer cannula 644 of surgical device 640, and a second lumen 804which is configured to receive an optical device, such as a light probeor a fiber optic bundle (not shown). Use of this arrangement permits useof additional surgical tools/instruments within outer sheath 102. Morespecifically, as the optical device is supported within the deliverysleeve 800, which, in turn, is connected to the surgical device, thesurgeon can simultaneously differentiate between abnormal and healthytissue, and resect tissue, all with by just holding the surgical device640. As a result, the surgeon may also choose to utilize a separatecautery device within outer sheath 102 to permit cauterization of anyvessels during the resection, in real time, and without requiringremoval of the surgical device 640.

Because outer sheath 102 may be directly positioned at area of interest500 in such a manner as to avoid unnecessary damage to criticalstructures, and because surgical device 640 may be placed directly atthe sight of area of interest, utilizing surgical access system 100provides the ability to resect most of an area of interest 500, such atumor. As one of ordinary skill in the art can appreciate, the more thata tumor is resected and removed, the less therapy is required fortreatment. In other words, the more diseased tissue there is resected,the less diseased tissue there is to destroy.

Once a cytoreductive resection of area of interest 500 has beencompleted, the process then proceeds to step 436. In step 436 a decisionis made to either remove outer sheath 102 or to leave outer sheath 102in position. More specifically, for some therapy applications, removalof outer sheath 102 may be more effective than leaving outer sheath inplace to deliver the therapy. If the decision is made to remove outersheath 102, after removal of outer sheath 102, the process 400 proceedsto step 438.

As one of ordinary skill in the art may appreciate, the naturalelasticity of brain tissue will maintain access or a corridor to area ofinterest 500 for period of time. In step 438, while the corridor isstill intact after removal of outer sheath 102, in one exemplaryarrangement, a delivery device may be inserted into the corridor todeliver irrigation to the surgical site. In some instances, a syringemay be inserted into the corridor to deliver an irrigating fluid, suchas saline directly to the surgical site. In another exemplaryconfiguration, a drainage catheter (which is configured with a pluralityof small openings at its distal end) is delivered into the corridor suchthat the distal end of the catheter is placed at or adjacent thesurgical site. Irrigating fluid is then introduced into the proximal end(such, as for example, by operatively attaching a syringe barrel to theproximal end), to deliver the irrigating fluid to the surgical site. Theirrigating fluid flushes out debris and assists in the brain tissue'snatural tendency to close back in on itself. Once the surgical site hasbeen irrigated, it may also be desirable to deliver certain therapiesdirectly to the surgical site, thereby avoiding therapy issuestraditionally encountered by the blood brain barrier. For example,certain therapies that may be provided in liquid form may be directlyinjected through the corridor, just prior to the tissue closing back inon itself. Because the corridor is closing, the therapy will be held inplace at the surgical site, thereby increasing its effectiveness at thesite and surrounding tissue.

In some therapy methodologies, outer sheath 102 may be necessary to aidin the delivery and/or placement of such therapy, as will be explainedin further detail below. Accordingly, if the decision in step 436 ismade to keep outer sheath 102 in place after completion ofcytoreduction, the process 400 proceeds to step 442.

In step 442, area of interest/surgical site 500 is irrigated to againremove any debris from the area. Irrigation may be performed in the samemanner as discussed in step 438, except through outer sheath 102. Onceirrigation is complete, the process proceeds to step 444.

In step 444 a therapy is delivered to area of interest 500. In oneexemplary configuration, intraoperative radiotherapy (IORT) may beemployed, so as to deliver therapy directly to area of interest 500through outer sheath 102. In one exemplary configuration, an implantabletherapy may be applied to area of interest 500. Example of animplantable therapy include: bioabsorbable radiation pellets, wafers ormesh, such as, for example, those manufactured by Nano-Rad LLC. Otherexamples include, but are not limited to, titanium capsules or seedswith radiation contents, bioabsorbable gels or foams that containradioactive, chemotherapy or immunotherapy agents.

In another exemplary configuration, a balloon catheter may be used toperform brachytherapy following the removal of diseased tissue at areaof interest 500. For example, a balloon catheter may be inserted throughouter sheath 102 and delivered to area of interest, and then the ballooncatheter may be inserted with a predetermined amount of radioactivesolution followed by the delivery of radiation to the surroundingtissues. A commercially available catheter that may be used includes theGliaSite balloon catheter, with an Iotrex radioactive solution. Use of aballoon catheter may provide a more targeted delivery of liquidradiation, thereby reducing impact on brain tissues surrounding thediseased tissue.

In another exemplary arrangement, an electron beam driven X-ray sourcemay be provided. One such exemplary configuration is the ZeissINTRABEAM®. The electrons are generated and accelerated in a main unitand travel via an electron beam drift tube which is surrounded by aconical applicator sheath such that its tip lies at an epicenter of anapplicator sphere to provide a point source of low energy X-rays at thetip. With this configuration, a nearly isotropic field of low energy isemitted.

In operation, the applicator sheath is inserted through outer sheath 102and into the surgical cavity at area of interest 500. An intraoperativeultrasound may be performed to determine the distance of the applicatorsurface to the skin, to avoid significant skin doses. The applicatorsheath may be secured into place by the surgeon using subcutaneoussutures around the neck of the sphere, similar to that described abovein connection with outer sheath 102.

In another exemplary arrangement, a photodynamic therapy may be used,whereby a predetermined chemical composition may provided to the patientand the chemical composition may be selectively activated by apredetermine wavelength, thereby achieving a therapeutic reaction. Forexample, in one exemplary configuration, illuminating ring 300 may beturned on to achieve the therapeutic reaction. In another exemplaryconfiguration, a light source, such as, for example, a fiber opticbundle, may be directed through outer sheath 102, either directlythrough outer sheath 102 or through delivery sleeve 800.

In yet another exemplary configuration, external beam high frequencyultrasound or interstitial high frequency ultrasound may also bedelivered through outer sheath and directly to area of interest 500.

In yet a further exemplary configuration, as shown in FIGS. 21A-21B, animplantable delivery device 900/900′ may be provided. Implantabledelivery device 900/900′ includes a neck portion 902 that is connectedto a body portion 904/904′. Both neck portion 902 and body portion904/904′ may be constructed of a relatively soft and flexible material.Body portion 904/904′ defines a reservoir for holding a therapeuticagent therein. A proximal end 905 of neck portion 902 is largely closed,with access to an interior of implantable delivery device 900/900′ beingproviding by a luer port 906. More specifically, therapy agents areintroduced into delivery device 900/900′ through luer port 906. Asealing flange 908 may further be provided, that operatively connects toneck portion 902 to assist in holding implantable delivery device900/900′ in place within the brain.

In the arrangement shown in FIG. 21A, body portion 904 may be providedwith at least one small opening 910. In one exemplary arrangement, aplurality of small openings 910 are provided, and such openings may bespaced equi-distance from one another about the periphery of bodyportion 904. Small openings 910 are configured to permit the therapyagent that is introduced through luer port 906 to weep out of thereservoir formed by body portion 904 at a controlled rate to increaseeffectiveness. Alternatively, body portion 900 may be configured as apermeable membrane that permits slow and controlled passage of therapyfrom the reservoir to the brain tissue 1000.

In an alternative arrangement shown in FIG. 21B, body portion 904′ maybe provided with flexible finger-like projections 912. In one exemplaryconfiguration, projections 912 are spaced equi-distance from one anotherabout the periphery of body portion 904′. Projections 912 extendoutwardly from an outer periphery of body portion 904′ and may be formedwith channels that provide communication between the reservoir and smallopenings 914 configured at distal tips 916 of projections 912. Openings914 are configured to permit the therapy agent that is introducedthrough luer port 906 to weep out of the reservoir. Projections 914assist in frictionally retaining delivery device 900′ at a target site.

Referring back to process 400, if delivery device 900/900′ is employed,delivery device 900/900′ is inserted at area of interest 500 throughouter sheath 102. Once positioned, outer sheath 102 is removed, andsealing flange 908 is operatively connected to neck portion 902 suchthat luer port 906 is accessible. Sealing flange 908 is configured toextend over the periphery of the surgical access opening that was formedthrough the skull 1002, thereby providing protection for the exposedbrain tissue 1000. The therapeutic agent may be supplied to thereservoir formed by body portion 904/904′ either before delivery device900/900′ is positioned at area of interest 500, or after sealing flange908 is in place. Sealing flange 908, as well as body portion 904/904′and neck portion 902 may be configured with flexible material to allowfor sealing against the dura and bone of the brain.

In yet another alternative arrangement involving delivery device900/900′, a transfer material may be delivered through outer sheath 102,similar to a foam that is configured to conform to the cytoreducted areaof interest 500. The foam will allow continuous contact with the therapyagent that weeps through body portion 904/904′ to provide a controlleddosage of therapy to area of interest 500.

After surgery and therapy on the target tissue is complete, the processproceeds to step 446. In this step, the instruments used for surgeryand/or therapy are removed from outer sheath 102. As the target tissueis removed, brain tissue will naturally fill the void formed by removingarea of interest 500 so that healthy brain tissue underlying the nowremoved target tissue is adjacent the end of outer sheath 102. Outersheath 102 is then gently removed and the brain tissue will naturallyfill and reclaim the space formerly occupied by the abnormality andouter cannula 102, aided by the irrigation of area of interest 500.Moreover, as the brain tissue reclaims the space formerly occupied bythe abnormality and outer cannula 102, implanted therapies, such as, forexample, bioabsorbable radiation pellets, wafers or mesh, will be heldin place at area of interest 500 to provide effective treatment, allpositioned beyond the blood brain barrier. While this process may takeseveral minutes, it is relatively atraumatic. Once outer sheath 102 hasbeen removed, the process continues to step 448, whereby the dura, skulland scalp are then closed in a known manner and the process ends. In theexemplary cases whereby a treatment device may be implanted, fullreclaiming of the space is delayed due to the implant until implant isexplanted or absorbed.

Because the location of the area of interest will vary from patient topatient, in one exemplary arrangement, it is contemplated that surgicalaccess system 100 will be provided as part of a kit. More specifically,it is contemplated that a set of multiple obturators 104 may be providedthat have different lengths and/or diameters. The set may be provided ina container that is configured be sterilized, with obturators 104secured therein. It is also contemplated that a set of manipulationtools 700/700′ may also be provided with the kit, and that manipulationtools 700/700′ may be positioned within the container for selectivesterilization. Outer sheath 102 may be provided with the kit, in variouslengths and diameters that correspond to the lengths and diameters ofobturators 104 provided in the kit. However, in one exemplaryarrangement, outer sheaths 104 are provided separately as single usedevices, in sterilized pouches.

Referring to FIG.

It will be appreciated that the surgical access system and methodsdescribed herein have broad applications. The foregoing embodiments werechosen and described in order to illustrate principles of the methodsand apparatuses as well as some practical applications. The precedingdescription enables others skilled in the art to utilize methods andapparatuses in various embodiments and with various modifications as aresuited to the particular use contemplated. In accordance with theprovisions of the patent statutes, the principles and modes of operationof this disclosure have been explained and illustrated in exemplaryembodiments.

It is intended that the scope of the present methods and apparatuses bedefined by the following claims. However, it must be understood thatthis disclosure may be practiced otherwise than is specificallyexplained and illustrated without departing from its spirit or scope. Itshould be understood by those skilled in the art that variousalternatives to the embodiments described herein may be employed inpracticing the claims without departing from the spirit and scope asdefined in the following claims. The scope of the disclosure should bedetermined, not with reference to the above description, but shouldinstead be determined with reference to the appended claims, along withthe full scope of equivalents to which such claims are entitled. It isanticipated and intended that future developments will occur in the artsdiscussed herein, and that the disclosed systems and methods will beincorporated into such future examples. Furthermore, all terms used inthe claims are intended to be given their broadest reasonableconstructions and their ordinary meanings as understood by those skilledin the art unless an explicit indication to the contrary is made herein.In particular, use of the singular articles such as “a,” “the,” “said,”etc. should be read to recite one or more of the indicated elementsunless a claim recites an explicit limitation to the contrary. It isintended that the following claims define the scope of the invention andthat the method and apparatus within the scope of these claims and theirequivalents be covered thereby. In sum, it should be understood that theinvention is capable of modification and variation and is limited onlyby the following claims.

What is claimed is:
 1. A surgical access assembly, comprising an outersheath defined by an open distal end and an open proximal end andincluding a hollow body portion therebetween; an obturator defined by adistal end and a proximal end, a body portion therebetween, and has acentral channel formed within the body portion, wherein the distal endfurther comprises a tapered distal tip member that terminates in aclosed radiused distal tip; a navigational probe configured to becoupled to a navigation system to indicate the position of the outersheath when the obturator is in an introducing configuration, whereinthe navigational probe is selectively seated within the central channel;and a locking member that is operatively connected to the proximal endof obturator, the locking member extending transversely through theproximal end of the obturator and into the central channel of theobturator to selectively engage the navigational probe to lock thenavigational probe against movement and to lock the navigational probeto the obturator; wherein the obturator is configured to be receivedwithin the outer sheath such that the tapered distal tip memberprotrudes from the open distal end of the outer sheath when theobturator is in an introducing configuration.
 2. The surgical accessassembly of claim 1, wherein the central channel further comprises afirst channel segment and a second channel segment.
 3. The surgicalaccess assembly of claim 1, wherein the obturator further comprises ahandle portion fixedly connected to the proximal end of the obturator,wherein the handle portion further comprises a first stop member and agrip member.
 4. The surgical access assembly of claim 3, wherein thelocking member is operatively connected to the handle portion.
 5. Thesurgical access assembly of claim 4, further comprising an engagementopening that is in communication with a receiving aperture that receivesthe locking member, wherein the engagement opening is in communicationwith a channel that receives a retaining member that is configured toretain the locking member to the handle portion.
 6. The surgical accessassembly of claim 1, wherein the body portion further comprises at leastone void area.
 7. The surgical access assembly of claim 1, wherein thebody portion of the obturator further comprises at least onecompensating protuberance on an outer surface of the body portion of theobturator, spaced distally from a proximal end of the obturator.
 8. Thesurgical access assembly of claim 1, wherein the central channelterminates in a depression that aligns with a proximal edge of thetapered distal tip member.
 9. The surgical access assembly of claim 8,wherein the depression comprises planar surfaces that converge inwardlyto form a seat that selectively receives a distal tip of thenavigational probe.
 10. The surgical access assembly of claim 1, furtherincluding at least one cross web extending transverse to the centralchannel.
 11. The surgical access assembly of claim 1, wherein thenavigational probe is selectively removeable from the central channel.12. The surgical access assembly of claim 1, wherein the obturatorfurther comprises a handle portion having a central access openingformed on a proximal end of the handle portion, the central accessopening that is in communication with the central channel.
 13. Thesurgical access assembly of claim 12, wherein the access opening furtherincludes an inwardly extending chamber that tapers toward the accessopening.
 14. The surgical access assembly of claim 1, wherein thenavigational probe extends proximally from the obturator when in anoperational position and is operatively connected to a navigationsystem.
 15. A surgical access assembly, comprising an outer sheathdefined by an open distal end and an open proximal end and including ahollow body portion therebetween; an obturator defined by a distal endand a proximal end, and having a body portion therebetween, wherein theobturator further includes a grip member disposed at the proximal endand a stop member disposed distal to the grip member and proximal to thebody portion, and wherein a central channel is formed within the bodyportion, wherein the distal end further comprises a tapered distal tipmember; a navigational element associated with the distal tip member ofthe obturator; and wherein the obturator is configured to be receivedwithin the outer sheath such that the tapered distal tip memberprotrudes from the open distal end of the outer sheath when theobturator is in an introducing configuration, the stop member preventingthe grip member from coming into contact with the proximal end of theouter sheath so as to create a gap between the grip member and theproximal end of the outer sheath, and the navigational element indicatesthe location of the distal tip member of the obturator to navigate thedistal tip of the obturator.
 16. The surgical access assembly of claim15, wherein the central channel further comprises a first channelsegment and a second channel segment separated by a transverse crossweb.